1. Field of the Invention
The present invention relates to a method of manufacturing a solid state imaging device, the solid state imaging device, and a camera using the solid state imaging device.
2. Description of the Related Art
CCD solid state imaging devices used for area sensors and the like have a configuration in which a photo-electric conversion portion array including a plurality of photo-electric conversion parts and a transfer electrode array including a plurality of transfer electrodes are arranged in parallel to each other on a semiconductor substrate. The transfer electrode array is disposed on charge transfer paths formed in the semiconductor substrate, and the plurality of transfer electrodes are sequentially driven, whereby charges are transferred along the charge transfer paths.
Particularly, in a CCD solid state imaging device of the inter-transfer type, the transfer electrode array is covered with a light-shielding layer to prevent light from being incident on the charge transfer paths. The light shielding by the light-shielding layer is for preventing the smear phenomenon, i.e., the appearance of a line on a screen through a change in the amount of charges being transferred, which would occur if light is incident on the charge transfer path during transfer of a charge sequentially to the lower side of the transfer electrode in the adjacent pixel in a CCD solid state imaging device. As the material of the light-shielding layer, in general, such a metallic material as aluminum, tungsten and molybdenum is used. For forming the light-shielding layer, a light-shielding layer material layer is formed by sputtering or CVD on the semiconductor substrate provided with the photo-electric conversion parts and the transfer electrode array. As a result, the light-shielding layer material layer is formed not only on the upper surfaces and side wall surfaces of the transfer electrode array to be light-shielded but also on the surfaces on the photo-electric conversion parts. Subsequently, therefore, the light-shielding material on the photo-electric conversion parts is removed by etching so that the photo-electric conversion parts come to be able to receive light. A solid state imaging device having this kind of light-shielding layer is described, for example, Japanese Patent Laid-open No. Hei 10-178166.